Hoechst Aktiengesellschaft

Franz Mayer

Herbert Fitz

Gerhard Gebauer

Jurgen Kuhls

Kurt Kraft

Johannes Brandrup

Coating formulations having improved adhesion are described which are especially suitable as primer for top coats of fluorocarbon polymers, which comprise (a) a copolymer of tetrafluoroethylene units, units of a perfluoroalkylvinyl ether and optionally units of hexafluoropropylene or vinylidene fluoride, (b) optionally dispersed polytetrafluoroethylene particles in addition, (c) a mixture of lithium hydroxide and suspended fine-particle pyrogenic SiO.sub.2, and (d) water as liquid carrier. The coating formulations are applied according to known methods to substrates such as metals, glass or ceramic surfaces. They may be used as single-layer systems without top coat, or as primer, the top coat being applicable immediately after a short-time drying only. Application fields are the coating of household equipment or technical apparatus, where a high-grade adhesion onto the substrate, combined with anti-adhesive properties and a smooth surface are obtained.

Coating and primer formulation on the basis of a copolymer of

Fluoropolymer dispersions containing colloidal particles of a partially modified tetrafluoroethylene polymer, the fluoropolymer resin powder obtained therefrom by coagulation and a process for the preparation of the dispersions mentioned are described. The particles have a three-shell particle structure, the particle core and the other particle shell consisting of a tetrafluoroethylene polymer provided with a modifying fluoro-olefinic comonomer and the inner particle shell consisting of tetrafluoroethylene homopolymer. Fluoro-olefins, perfluoro-olefins, halogenofluoro-olefins and completely or partially fluorinated vinyl ethers are used as the modifying comonomers. The preparation is effected by the seed technique or intermediate letting down method, the modified core being formed in the first phase and the modifying comonomer being subsequently metered into the continuing tetrafluoroethylene polymerization in the second phase. The resins obtained are particularly suitable for the paste extrusion process for producing cable insulation and highly stretchable, unsintered tapes, and, after appropriate working up, also for the ram extrusion and the press-sinter technique.

Fluoropolymers with shell-modified particles, and processes for their

The invention provides a high temperature resistant anti-adhesion and slide lacquer composed substantially of finely distributed low molecular polytetrafluorethylene, a polytriketo-imidazolidine resin and a solvent or solvent mixture. The system of the invention may be applied to the substrate in one single operation.

Coating composition

Shaped structures containing polytetrafluoroethylene are connected with themselves or with another material stable up to 400.degree.C under elevated pressure and temperature using as interlayer between the surfaces to be connected at least one copolymer of tetrafluoroethylene and perfluoroalkyl-perfluorovinyl units in a determined proportion. The composites obtained have a high mechanic strength and the joint has good temperature endurance properties.

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Burgkirchen, Alz, Germany

Franz Mayer